Heater Blockoff Plate
Silencer Oil Bath Air Cleaner
Trico Washer Pump
Believe it or not, back in 1956 -- you could order a car to *not* have a heater. This is the blockoff plate kit for your 1956 Buick.
Century, Super and Roadmaster series with the 322 cubic inch engine had an oil bath air cleaner that had a large "silencer" (or snorkel as some call it). Here is an example of an original untouched one. The color should be underhood black, and you can buy a reproduction of the orance AC decal that you see on the silencer. There is a small mount bracket that supports the silencer from the bottom and attaches to the top of the thermostat housing, which is shown in the last picture.
cam-o-matic windshield wipers with coordinator had this Trico Washer Pump installed to squirt washer fluid from the cabin by pumping/pushing the button on the wiper switch. You can buy a reproduction of the lid, the sticker and I believe the glass jar -- but not the coordinator / pump nor the bracket that is used to attach to the firewall.